phpStorm losing keyboard input

You should look at this bug here: http://youtrack.jetbrains.com/issue/IDEA-79312

It's exactly your issue, and it has a potential workaround:

sudo ibus restart

Hope that helps!

Seems like the correct issue/bug for OP is actually this: IDEA-78860

This is not a Ubuntu version specific, but X Window / IBus problem and it is still happening in Ubuntu 14.04 with IBus < 1.5.11

Option 1:
Update IBus to 1.5.11 or higher Check this answer on how to update ibus on ubuntu

Option 2:
Official workaround, is to add following line to your ~/.profile

export IBUS_ENABLE_SYNC_MODE=1

Remember you have to restart your session (logout) for this to take effect.

Option 3:
The most universal workaround is still ibus restart, but I think it is worth to quote the assignee of the issue:

Restarting IBus isn't recommended (may crash the IDE later)

Yes, that may happen sooner or later. Also this resets your keyboard layout to default (mostly english). So you'd have change that back every time you restart ibus.

Another option is to disable ibus, but this really is not a solution for people who do not have US kb layout.